obtaining a current coding block comprising a plurality of sub-blocks arranged in an array;

dividing the current coding block into at least two areas, wherein each area of the at least two areas comprises two or more of the plurality of sub-blocks;

setting a corresponding control point motion vector (CPMV) for each of one or more control points in each area of the at least two areas, respectively; and

affine-predicting motion vectors (MVs) of the two or more of the plurality of sub-blocks in each area of the at least two areas, using the corresponding CPMV,

wherein for each of the one or more control points in the each area, in response to the control point of the each area being an original control point of the current coding block, a CPMV of the original control point of the current coding block is used as the CPMV of the control point of the each area; and

for one of the one or more control points in one of the at least two areas, in response to the control point of the one area being not the original control point of the current coding block, and in response to a MV of any sub-block of the one area being able to be calculated from a known CPMV of another one of the at least two areas adjacent to the one area, a MV of a sub-block, which is located in the another area and is adjacent to a sub-block where the control point is located, is used as the CPMV of the control point of the one area.